Soviet locomotive class AA20

In Whyte notation, a 4-14-4 locomotive has a two-axle pilot truck, seven coupled driving axles, and a two-axle trailing truck. A single example of this type, called the A. Andreev, was built. A group of Soviet locomotive engineers had visited the United States, and presumably they had seen the 4-12-2 locomotives being used by the Union Pacific. The 4-14-4 has some common features with the UP engines, success not being one of them.

The seven driving axles made for a very long rigid wheelbase, and provisions were made to negotiate curves. The center three driving axles were "blind," i.e. flangeless. This would allow some side to side movement over the railhead. The side rods connecting the first and second and sixth and seventh axles had universal joints.

The Andreev locomotive was a disaster - it tended to destroy the railroad switches it traveled over and derailed almost every time it moved. It was too powerful for the couplers in use at the time and its boiler was too small to provide sufficient steam.

After a publicity trip to Moscow, the Andreev was put into storage and then scrapped.